Population Pharmacokinetic Analysis of Daclatasvir in Subjects with Chronic Hepatitis C Virus Infection

Beyond Rule of Five and PROTACs in Modern Drug Discovery: Polarity Reducers, Chameleonicity, and the Evolving Physicochemical Landscape

Developing orally bioavailable drugs demands an understanding of absorption in early drug development. Traditional methods and physicochemical properties optimize absorption for rule of five (Ro5) compounds; beyond rule of five (bRo5) drugs necessitate advanced tools like the experimental measure of exposed polarity (EPSA) and the AbbVie multiparametric score (AB-MPS). Analyzing AB-MPS and EPSA against ∼1000 compounds with human absorption data and ∼10,000 AbbVie tool compounds (∼1000 proteolysis targeting chimeras or PROTACs, ∼7000 Ro5s, and ∼2000 bRo5s) revealed new patterns of physicochemical trends. We introduced a high-throughput "polarity reduction" descriptor: ETR, the EPSA-to-topological polar surface area (TPSA) ratio, highlights unique bRo5 and PROTAC subsets for specialized drug design strategies for effective absorption. Our methods and guidelines refine drug design by providing innovative in vitro approaches, enhancing physicochemical property optimization, and enabling accurate predictions of intestinal absorption in the complex bRo5 domain.

Need for a Standardized Translational Drug Development Platform: Lessons Learned from the Repurposing of Drugs for COVID-19

In the absence of drugs to treat or prevent COVID-19, drug repurposing can be a valuable strategy. Despite a substantial number of clinical trials, drug repurposing did not deliver on its promise. While success was observed with some repurposed drugs (e.g., remdesivir, dexamethasone, tocilizumab, baricitinib), others failed to show clinical efficacy. One reason is the lack of clear translational processes based on adequate preclinical profiling before clinical evaluation. Combined with limitations of existing in vitro and in vivo models, there is a need for a systematic approach to urgent antiviral drug development in the context of a global pandemic. We implemented a methodology to test repurposed and experimental drugs to generate robust preclinical evidence for further clinical development. This translational drug development platform comprises in vitro, ex vivo, and in vivo models of SARS-CoV-2, along with pharmacokinetic modeling and simulation approaches to evaluate exposure levels in plasma and target organs. Here, we provide examples of identified repurposed antiviral drugs tested within our multidisciplinary collaboration to highlight lessons learned in urgent antiviral drug development during the COVID-19 pandemic. Our data confirm the importance of assessing in vitro and in vivo potency in multiple assays to boost the translatability of pre-clinical data. The value of pharmacokinetic modeling and simulations for compound prioritization is also discussed. We advocate the need for a standardized translational drug development platform for mild-to-moderate COVID-19 to generate preclinical evidence in support of clinical trials. We propose clear prerequisites for progression of drug candidates for repurposing into clinical trials. Further research is needed to gain a deeper understanding of the scope and limitations of the presented translational drug development platform.

A pharmacometric approach to evaluate drugs for potential repurposing as COVID-19 therapeutics

INTRODUCTION

Developing and evaluating novel compounds for treatment or prophylaxis of emerging infectious diseases is costly and time-consuming. Repurposing of already available marketed compounds is an appealing option as they already have an established safety profile. This approach could substantially reduce cost and time required to make effective treatments available to fight the COVID-19 pandemic. However, this approach is challenging since many drug candidates show efficacy in in vitro experiments, but fail to deliver effect when evaluated in clinical trials. Better approaches to evaluate in vitro data are needed, in order to prioritize drugs for repurposing.

AREAS COVERED

This article evaluates potential drugs that might be of interest for repurposing in the treatment of patients with COVID-19 disease. A pharmacometric simulation-based approach was developed to evaluate in vitro activity data in combination with expected clinical drug exposure, in order to evaluate the likelihood of achieving effective concentrations in patients.

EXPERT OPINION

The presented pharmacometric approach bridges in vitro activity data to clinically expected drug exposures, and could therefore be a useful compliment to other methods in order to prioritize repurposed drugs for evaluation in prospective randomized controlled clinical trials.

Effective and Safe Daclatasvir Drug Exposures Predicted in Children Using Adult Formulations

BACKGROUND

Sofosbuvir (SOF)/daclatasvir (DCV) is the direct-acting antiviral regimen of choice in many low- and middle-income countries for curative treatment of chronic hepatitis C virus (HCV) infection in adults, but data on the use of DCV in children are lacking. We performed a population pharmacokinetic (PK) analysis to predict DCV exposure in children treated with available adult formulations.

METHODS

DCV concentration data from HCV-infected adolescents receiving SOF/DCV [400/60 mg, once daily (OD)] who participated in a PK study in Egypt were used for model development. PK parameters were estimated using a population approach. Monte Carlo simulations were run for virtual children weighing 10 to <35 kg receiving 60 or 30 mg OD, and DCV exposures were compared with adults ranges.

RESULTS

Seventeen HCV-infected adolescents (13 males) provided 151 DCV concentrations. Median (range) age was 14 (11-18) years and weight 50 (32-63) kg. In these adolescents receiving 60 mg DCV, median (interquartile range) DCV area under the concentration time curve 0 to 24 hours, maximum concentrations, and minimum concentrations were 11,130 (8140-14,690) ng·h/mL, 1030 (790-1220) ng/mL and 130 (110-220) ng/mL, respectively, compared with 10,343 (7661-14,095) ng·h/mL, 1132 (876-1518) ng/mL and 110 (55.7-192) ng/mL predicted in children 10 to <35 kg receiving 30 mg. The proportion of children with DCV exposures above the adult range rapidly increased for children <30 kg using 60 mg OD, similarly for children 10-14 kg using 30 mg.

CONCLUSIONS

DCV 30 mg OD was predicted to achieve effective and safe exposures in children 14 to <35 kg, perhaps down to 10 kg. These results should be validated clinically. Low-cost available adult DCV formulations together with approved pediatric doses of SOF would expand global access to HCV treatment for children.

Association of Sofosbuvir and Daclatasvir Plasma Trough Concentrations with Patient-, Treatment-, and Disease-Related Factors Among HIV/HCV-Coinfected Persons

BACKGROUND

Sofosbuvir plus daclatasvir achieves high rates of sustained virologic response (SVR), with no differences according to HIV serostatus. However, only limited information is available on the pharmacokinetic variability of sofosbuvir and daclatasvir in HIV/HCV-coinfected patients.

OBJECTIVES

The aim of this study was to identify patient-, treatment-, and disease-related factors that are significantly associated with sofosbuvir and daclatasvir plasma trough concentrations (C_trough), including liver and renal function, among HIV/HCV-coinfected persons.

METHODS

In this observational cohort pilot study, HIV/HCV-coinfected patients undergoing sofosbuvir plus daclatasvir treatment were prospectively enrolled. Biochemical and viro-immunological parameters were assessed at baseline, week 4 (W4), end of treatment (EOT), and after EOT. The FIB-4 score and CKD-EPI equation were used to estimate liver disease and glomerular filtration rate (eGFR), respectively. For sofosbuvir, sofosbuvir metabolite (GS-331007), and daclatasvir, C_trough was measured at W4 and week 8 (W8), and the mean of the values at those two time points (mean-C_trough) was calculated. The Mann-Whitney test and Spearman's rank correlation were used to evaluate the correlations between the mean-C_trough of each direct-acting antiviral (DAA) and the considered variables.

RESULTS

Thirty-five patients were included (SVR 94%). An increased GS-331007 mean-C_trough was significantly correlated with a decreased eGFR at W4 (rho = -0.36; p = 0.037) and EOT (rho = -0.34; p = 0.048). There was a significant correlation between daclatasvir mean-C_trough and FIB-4 at all time points: baseline (rho = -0.35; p = 0.037), W4 (rho = -0.44; p = 0.008), EOT (rho = -0.40; p = 0.023), and after EOT (rho = -0.39; p = 0.028).

CONCLUSIONS

In HIV/HCV-coinfected patients in a real-world setting, exposure to a high GS-331007 C_trough was associated with a slight decrease in renal function, while advanced hepatic impairment was significantly associated with a lower daclatasvir C_trough. Though the clinical and therapeutic relevance of these findings may be limited, increasing clinicians' knowledge regarding DAA exposure in difficult-to-treat patients could be relevant in single cases, and further investigations are warranted.

Population Pharmacokinetic Analysis of Yimitasvir in Chinese Healthy Volunteers and Patients With Chronic Hepatitis C Virus Infection

Yimitasvir is a novel, oral hepatitis C virus (HCV) non-structural protein 5A inhibitor for the treatment of chronic HCV genotype 1 infection. The objective of this analysis was to develop a population pharmacokinetic model of yimitasvir in Chinese healthy volunteers and HCV infection patients. The model was performed using data from 219 subjects across six studies. Nonlinear mixed effects models were developed using Phoenix NLME software. The covariates were evaluated using a stepwise forward inclusion (p < 0.01) and then a backward exclusion procedure (p < 0.001). A two-compartment model with sequential zero-first order absorption and first-order elimination reasonably described yimitasvir pharmacokinetics (PK). The apparent oral clearance and central volume of distribution were 13.8 l·h⁻¹ and 188 l, respectively. The bioavailability (F) of yimitasvir decreased 12.9% for each 100 mg dose increase. Food was found to affect absorption rate (Ka) and F. High-fat meal decreased Ka and F by 90.9% and 38.5%, respectively. Gender and alanine aminotransferase were identified as significant covariates on apparent oral clearance. Female subjects had lower clearance than male subjects. Zero-order absorption duration was longer in healthy volunteers (2.17 h) than that in patients (1.43 h). The population pharmacokinetic model described yimitasvir PK profile well. Food decreased Ka and F significantly, so it was recommended to take yimitasvir at least 2 h before or after a meal. Other significant covariates were not clinically important.

Pharmacokinetics of daclatasvir in Egyptian adolescents with genotype-4 HCV infection

BACKGROUND

Daclatasvir has potent antiviral activity against HCV infection when used in combination with sofosbuvir, however, its pharmacokinetics have not been described in adolescents. The aim is to determine the pharmacokinetic parameters of daclatasvir in adolescents, and to develop a population pharmacokinetic (PopPK) model.

METHODS

Seventeen adolescent patients with genotype-4 chronic HCV infection received once daily oral daclatasvir 60 mg in combination with 400 mg sofosbuvir for 12 weeks. Steady state concentrations were determined. Non-compartmental and population PK were determined.

RESULTS

The average PK parameters calculated by non-compartmental analysis (NCA): maximum plasma concentration (C_max), area under the curve (AUC), apparent oral volume of distribution (V/F), apparent oral clearance (CL/F) and half-life (T_1/2) were 1,092 ng/ml, 11,178 ng/ml•h, 55 l, 4.5 l/h and 8.5 h, respectively. Daclatasvir was best described by one compartment structural PK model with zero order absorption and first-order elimination. The absorption rate constant (K₀), V/F, and CL/F of the final PopPK model of daclatasvir were 1.5/h, 52 l and 4.7 l/h, respectively. Body weight and serum albumin had significant effect on the V/F parameter.

CONCLUSIONS

Body weight and serum albumin were the major determinants of daclatasvir V/F in this population. PK parameters were comparable to those reported in adult HCV patients, demonstrating that 60 mg daclatasvir is an appropriate dose for adolescents. ClinicalTrials.gov NCT03540212.

Daclatasvir: A Review of Preclinical and Clinical Pharmacokinetics

Daclatasvir is a first-in-class, highly selective, hepatitis C virus, non-structural protein 5a polymerase replication complex inhibitor with picomolar potency and broad genotypic coverage in vitro. Daclatasvir undergoes rapid absorption, with a time to reach maximum plasma concentration of 1-2 h and an elimination half-life of ~ 10 to 14 h observed in single-ascending dose studies. Steady state was achieved by day 4 in multiple-ascending dose studies. Daclatasvir can be administered without regard to food or pH modifiers. Daclatasvir exposure is similar between healthy subjects and subjects infected with hepatitis C virus. Intrinsic factors such as age, race, or sex do not impact daclatasvir exposure. No dose adjustment is necessary for patients with any degree of hepatic or renal impairment. Daclatasvir has low-to-moderate clearance with the predominant route of elimination via cytochrome P450 3A4-mediated metabolism and P-glycoprotein excretion and intestinal secretion. Renal clearance is a minor route of elimination for daclatasvir. As a result, the dose of daclatasvir should be reduced from 60 to 30 mg once daily when co-administered with strong inhibitors of cytochrome P450 3A4. No dose adjustment is required when daclatasvir is co-administered with moderate inhibitors of cytochrome P450 3A4. The dose of daclatasvir should be increased from 60 to 90 mg once daily when co-administered with moderate inducers of cytochrome P450 3A4. Co-administration of daclatasvir with strong inducers of cytochrome P450 3A4 is contraindicated. Concurrent medications with inhibitory effects on P-glycoprotein without concurrent inhibition of cytochrome P450 3A4 are unlikely to cause marked changes in daclatasvir exposure, as the clearance of daclatasvir is through both cytochrome P450 3A4 and P-glycoprotein. The potential for daclatasvir to affect the pharmacokinetics of concomitantly administered drugs that are substrates of the cytochrome P450 enzyme system is low. In vitro, daclatasvir is a weak-to-moderate inhibitor of transporters including organic cation transporter 1, P-glycoprotein, organic transporting polypeptide 1B1, organic transporting polypeptide 1B3, and breast cancer resistance protein, although in clinical studies, daclatasvir has not altered the pharmacokinetics of concomitantly administered drugs that are substrates of these transporters to an appreciable degree, except for rosuvastatin. In summary, daclatasvir is a hepatitis C virus, non-structural protein 5a-selective inhibitor with a well-characterized pharmacokinetic profile that forms part of potent and well-tolerated all-oral treatment regimens for chronic hepatitis C virus infection.

Population pharmacokinetic modeling and simulation of HPPH in Chinese patients with esophageal carcinoma

1. 2-[1-Hexyloxyethyl]-2-devinyl pyropheophorbide-a (HPPH), a second-generation photosensitizer, has been widely employed in photodynamic therapy (PDT) for the treatment of malignant lesions. The objective of this study was to characterize the pharmacokinetics of HPPH in Chinese patients using a population pharmacokinetic (PopPK) approach.2. For the first time, a PopPK model of HPPH for Chinese (n = 20) was developed (registration number: CTR20160425). The pharmacokinetics of HPPH was described by a three-compartment model with linear elimination. Through the stepwise addition (p < 0.05) and backward elimination (p < 0.001) approach, fat-free mass (FFM) was identified to be the most significant covariate and V₁ increased with FFM. Visual predictive check (VPC) was employed for the evaluation of the final model. Subsequent full covariate analysis indicated that FFM has considerable impact (∼30%) on HPPH exposure and fat mass also has a modest (∼25%) impact.3. The simulations suggested that a dose adjustment of HPPH may be necessary for Chinese and the dose of 3 mg/m² should be appropriate. HPPH exposure increases with fat mass while being inversely related to FFM. HPPH-PDT for overweight patients should be monitored with more caution and PDT conditions should be optimized if necessary.

Gastric-acid-mediated drug-drug interactions with direct-acting antiviral medications for hepatitis C virus infection: clinical relevance and mitigation strategies

Drug-drug interactions (DDIs) between direct-acting antiviral (DAA) medications and acid-reducing agents mediated by gastric acid represent an important issue in drug development and treatment, which could lead to impaired bioavailability and subtherapeutic plasma concentrations of DAA drugs and subsequently compromised treatment outcomes. However, identification of clinically relevant drug interactions associated with elevated gastric pH is not well characterized. Here, we present the first comprehensive analysis of the gastric-acid-mediated drug interactions with all novel DAA medications by analyzing and revisiting in vitro data, prospective DDI trials and retrospective assessments based upon Phase II and III studies, aiming toward an in-depth understanding of the clinical implications and mitigation strategies to circumvent such interactions.

Population Pharmacokinetic Analysis of Daclatasvir, Asunaprevir, and Beclabuvir Combination in HCV-Infected Subjects

A fixed-dose combination of daclatasvir (pangenotypic NS5A inhibitor), asunaprevir (NS3/4A protease inhibitor), and beclabuvir (nonnucleoside NS5B inhibitor) was approved for hepatitis C virus treatment in Japan. The objectives of the analyses were to develop the daclatasvir, asunaprevir, and beclabuvir population pharmacokinetic models for the combination regimen. First, an original population pharmacokinetic model was developed using the data in non-Japanese hepatitis C virus-infected subjects. The model was subsequently updated after a phase 3 study in Japanese hepatitis C virus-infected subjects was available. A total of 11,382, 11,300, and 10,728 pharmacokinetic records from 1,228 subjects were included for daclatasvir, asunaprevir, and beclabuvir in the updated model, respectively. Daclatasvir and beclabuvir pharmacokinetics (PK) were described by a 1-compartment model with linear elimination and asunaprevir PK was described by 2-compartment model with linear elimination. Cirrhosis, baseline, and time-varying ALT were significant covariates on asunaprevir apparent oral clearance. Asian subjects had greater asunaprevir and beclabuvir exposures than white subjects. The effects of all covariates on daclatasvir PK were modest and not considered clinically significant. With the exception of race on asunaprevir and beclabuvir PK, no other parameters for daclatasvir, asunaprevir and beclabuvir population PK models were meaningfully impacted during the refinement with Japanese subjects.

Population Pharmacokinetic Analysis for Daclatasvir and Asunaprevir in Japanese Subjects With Chronic Hepatitis C Virus Infection

Daclatasvir is a nonstructural protein 5A replication complex inhibitor, and asunaprevir is a nonstructural protein 3 protease inhibitor for hepatitis C virus (HCV). In 2014, the combination therapy of daclatasvir and asunaprevir received the first global approval in Japan as the first nonribavirin, all‐oral therapy for HCV treatment. The population pharmacokinetics (popPK) of daclatasvir and asunaprevir were characterized by nonlinear mixed‐effects modeling using 3801 and 2626 concentration data from 336 and 265 Japanese HCV subjects, respectively. The plasma pharmacokinetic profiles of daclatasvir and asunaprevir were described by a 1‐compartment model. Parameter estimates (interindividual variability) of daclatasvir apparent clearance (CL/F) and apparent volume of the central compartment (V/F) were 5.29 L/h (39.4%) and 64.2 L (38.1%). The effects of all statistically significant covariates on daclatasvir PK parameters were within or overlapped the 80% to 125% boundaries, suggesting a lack of clinical relevance. Parameter estimates (interindividual variability) of asunaprevir CL/F and V/F were 52.1 L/h (41.5%) and 75.1 L (93.4%), respectively. Baseline and time‐varying aspartate aminotransferase (AST) and cirrhosis on CL/F and formulation (soft‐gel capsule or tablet) on F were included as significant covariates in the asunaprevir popPK model. The effects of all covariates exceeded the 80% to 125% boundaries, indicating that the asunaprevir soft‐gel capsule had higher bioavailability than the tablet and that asunaprevir exposure increased with cirrhosis and increasing baseline and time‐varying AST values. The popPK models adequately described the PK profiles of daclatasvir and asunaprevir in Japanese HCV subjects.

Integrated pharmacokinetic/viral dynamic model for daclatasvir/asunaprevir in treatment of patients with genotype 1 chronic hepatitis C

In order to develop an integrated pharmacokinetic/viral dynamic (PK/VD) model to predict long-term virological response rates to daclatasvir (DCV) and asunaprevir (ASV) combination therapy in patients infected with genotype 1 (GT1) chronic hepatitis C virus (HCV), a systematic publication search was conducted for DCV and ASV administered alone and/or in combination in healthy subjects or patients with GT1 HCV infection. On the basis of a constructed meta-database, an integrated PK/VD model was developed, which adequately described both DCV and ASV PK profiles and viral load time curves. The IC₅₀ values of DCV and ASV were estimated to be 0.041 and 2.45 μg/L, respectively, in GT1A patients. A sigmoid E_max function was applied to describe the antiviral effects of DCV and ASV, depending on the drug concentrations in the effect compartment. An empirical exponential function revealed that IC₅₀ changing over time described drug resistance in HCV GT1A patients during DCV or ASV monotherapy. Finally, the PK/VD model was evaluated externally by comparing the expected and observed virological response rates during and post-treatment with DCV and ASV combination therapy in HCV GT1B patients. Both the rates were in general agreement. Our PK/VD model provides a useful platform for the characterization of pharmacokinetic/pharmacodynamic relationships and the prediction of long-term virological response rates to aid future development of direct acting antiviral drugs.